WASHINGTON -- Sens. Mary Landrieu, D-La., and Kay Hagan, D-N.C., got a boost in their 2014 re-election prospects from their recent votes in favor of extended background checks for gun purchases, according to a new poll.

The background check vote last month fell six votes short of the 60 needed to overcome a Republican filibuster.

According to the poll by Public Policy Polling, 71 percent of Louisiana voters and 73 percent in North Carolina support background checks. The polling firm, based in North Carolina, does work mostly for Democratic and liberal organizations.

According to the poll, 44 percent of the 536 Louisiana voters surveyed said they are more likely to support Landrieu for re-election because she voted for the background check legislation, compared to 26 percent who say they are less likely to support her.

Landrieu also got a 6-point improvement in her net approval/disapproval rating from the last time Public Policy Polling surveyed state voters back in February. Her favorability rating increased from 47 percent approve/45 percent disapprove three months ago, to 49 percent approve/41 percent disapprove in the latest poll. The margin of error is +/-4.2 percent, according to the polling firm.

Rep. Bill Cassidy, R-Baton Rouge, who has announced he is running against Landrieu, said he would have opposed the Senate legislation expanding background checks. The House didn't vote on the legislation. Public Policy didn't ask voters about Cassidy in its new poll.

The same Public Policy Polling survey said that 40 percent of surveyed voters said they would be less likely to vote for Sen. David Vitter, R-La., based on his vote against extended background checks, vs. 25 percent who said they are more likely to support him.

The results varied significantly between women and men.

Fifty-one percent of women said they are more likely to support Landrieu because of her vote for background checks, compared to 36 percent of men.

Twenty-one percent of women said that the vote makes them less likely to support her in 2014, vs. 31 percent of men.

The poll said that 80 percent of Democrats surveyed in Louisiana support background checks compared to 61 percent of Republicans.

The Louisiana poll was conducted on April 30 and May 1 on behalf of Americans United for Change, a liberal advocacy group for causes like clean energy and health-care overhaul.

Public Policy Polling, founded in 2001 by North Carolina businessman Dean Debnam, does work on behalf of Democratic and progressive causes. It's become well-known for asking unusual questions, such as whether President Barack Obama would be eligible to enter heaven in the event of Rapture -- 44 percent said he would and 26 percent he would not.

"Mary Landrieu and Kay Hagan helped their chances for re-election by supporting background checks," Debnam said. "Their constituents overwhelmingly support the stance they took on this issue and are ready to reward them for it at the ballot box next year."

"The Manchin-Toomey compromise was a
hard-fought but balanced approach that would reduce gun violence and make it much
harder for criminals and mentally ill individuals to access guns. Currently,
guns can be purchased online and at gun shows without any background check
whatsoever, leaving a gaping hole in our gun protection system."

"I believe that we must do a better job
of keeping guns out of the hands of criminals. I'm confident that most people
understand the importance of closing this loophole while preserving the rights
of law abiding individuals to own and use guns for hunting, sport and self-protection."

Here's how Cassidy explained his
opposition:

"Background checks are already the law. This is not the issue. Sen. Landrieu voted for a bill which would not have prevented the tragedy of Sandy Hook or the tragedy of inner city gun violence but would have expanded the size and scope of government and infringed upon law abiding citizens."

Last year, 74 percent of Louisiana voters approved a constitutional amendment that would require "strict scrutiny" for any restrictions on the right to keep and bear arms.